[clang] [flang] [llvm] [flang] Add runtime trampoline pool for W^X compliance (PR #183108)

[Kelvin Li via cfe-commits]

================
@@ -0,0 +1,13 @@
+! Test that -fsafe-trampoline is properly forwarded from driver to
+! frontend, and that -fno-safe-trampoline (default) works.
+
----------------
kkwli wrote:

The option is ignored on AIX.
```
flang-23: warning: ignoring '-fsafe-trampoline' option as it is not currently supported for target 'powerpc64-ibm-aix7.2.0.0' [-Woption-ignored]
```


```suggestion
! UNSUPPORTED: system-aix
```

https://github.com/llvm/llvm-project/pull/183108